(1) Field of the Invention
The present patent application relates to intensifying the cleaning performance of washing agents when washing textiles, by the use of a specific soil-release-enabling polymer.
(2) Description of Related Art, Including Information Disclosed Under 37 C.F.R. §§1.97 and 1.98
Washing agents generally contain, in addition to the ingredients such as surfactants and builder materials that are indispensable for the washing process, further constituents that can be grouped under the heading of “washing adjuvants” and encompass such different groups of active substances as foam regulators, graying inhibitors, bleaching agents, bleach activators, and color transfer inhibitors. Also among such adjuvants are substances that impart soil-repelling properties to the laundry fibers and, if present during the washing operation, support the soil-releasing capability of the other washing-agent constituents. The same also applies analogously to cleaning agents for hard surfaces. Soil-release-enabling substances of this kind are often referred to as “soil release” active substances or, because of their ability to make the treated surface (for example, of the fibers) soil-repellent, as “soil repellents.” For example, the soil-release-enabling action of methyl cellulose is known from U.S. Pat. No. 4,136,038. European Patent Application EP 0 213 729 discloses decreased redeposition with the use of washing agents that contain a combination of soap and a nonionic surfactant having alkylhydroxyalkyl cellulose. European Patent Application EP 0 213 730 discloses textile treatment agents that contain cationic surfactants and nonionic cellulose ethers having HLB values from 3.1 to 3.8. U.S. Pat. No. 4,000,093 discloses washing agents that contain 0.1 wt % to 3 wt % alkyl cellulose, hydroxyalkyl cellulose, or alkylhydroxyalkyl cellulose as well as 5 wt % to 50 wt % surfactant, the surfactant component being made up substantially of C10 to C13 alkyl sulfate and up to 5 wt % C14 alkyl sulfate, and less than 5 wt % alkyl sulfate having alkyl radicals of C15 and above. U.S. Pat. No. 4,174,305 discloses washing agents that contain 0.1 wt % to 3 wt % alkyl cellulose, hydroxyalkyl cellulose, or alkylhydroxyalkyl cellulose, as well as 5 wt % to 50 wt % surfactant, the surfactant component being made up substantially of C10 to C12 alkylbenzenesulfonate and comprising less than 5 wt % alkylbenzenesulfonate having alkyl radicals of C13 and above. European Patent Application EP 0 634 481 relates to a washing agent that contains alkali percarbonate and one or more nonionic cellulose derivatives. Explicitly disclosed among the latter are only hydroxyethyl cellulose, hydroxypropyl cellulose, and methyl cellulose, and (in the context of the Examples) the methylhydroxyethyl cellulose Tylose® MH50, the hydroxypropylmethyl cellulose Methocel® F4M, and hydroxybutyl cellulose. European Patent EP 0 271 312 (P&G) relates to soil-release-enabling active substances, among them cellulose alkyl ethers and cellulose hydroxyalkyl ethers (with DS of 1.5 to 2.7 and molar weights from 2,000 to 100,000) such as methyl cellulose and ethyl cellulose, which are to be used with peroxygen bleaching agents at a weight ratio (based on the active oxygen content of the bleaching agent) from 10:1 to 1:10. European Patent EP 0 948 591 B1 discloses a washing agent in liquid or granular form that imparts, to fabrics and textiles washed therewith, textile appearance advantages such as decreased pilling and linting, color fading prevention, improved abrasion resistance, and/or enhanced softness, and that contains 1 to 80 wt % surfactant, 1 to 80 wt % organic or inorganic builder, 0.1 to 80 wt % of a hydrophobically modified nonionic cellulose ether having a molar weight from 10,000 to 2,000,000, the modification consisting in the presence of optionally oligomerized (degree of oligomerization up to 20) ethyleneoxy- or 2-propyleneoxy-ether units and of C8 to C24 alkyl substituents, and such that the alkyl substituents must be present in quantities from 0.1 to 5 wt % based on the cellulose ether material.
Because of their chemical similarity to polyester fibers, soil-release-enabling active substances that are particularly active for textiles made of said material are copolyesters that contain dicarboxylic acid units, alkylene glycol units, and polyalkylene glycol units. Soil-release-enabling copolyesters of the aforesaid kind, and the use thereof in washing agents, have been known for some time.
German Application DT 16 17 141, for example, describes a washing method using polyethylene terephthalate-polyoxyethlene glycol copolymers. German Application DT 22 00 911 relates to washing agents that contain nonionic surfactant and a mixed polymer of polyoxyethylene glycol and polyethylene terephthalate. German Application DT 22 53 063 recites acid textile finishing agents that contain a copolymer of a dibasic carboxylic acid and an alkylene or cycloalkylene polyglycol as well as, if applicable, an alkylene or cycloalkylene glycol. Polymers of ethylene terephthalate and polyethylene oxide terephthalate in which the polyethylene glycol units have molecular weights from 750 to 5,000 and the molar ratio of ethylene terephthalate to polyethylene oxide terephthalate is 50:50 to 90:10, and the use thereof in washing agents, are described in German Patent DE 28 57 292. Polymers, having a molecular weight of 15,000 to 50,000, of ethylene terephthalate and polyethylene oxide terephthalate, the polyethylene glycol units having molecular weights from 1,000 to 10,000 and the molar ratio of ethylene terephthalate to polyethylene oxide terephthalate being 2:1 to 6:1, can be used according to German Application DE 33 24 258 in washing agents. European Patent EP 066 944 relates to textile treatment agents that contain a copolyester of ethylene glycol, polyethylene glycol, aromatic dicarboxylic acid, and sulfonated aromatic dicarboxylic acid in specific molar ratios. European Patent EP 185 427 discloses polyesters, end-capped with methyl or ethyl groups, having ethylene and/or propylene terephthalate and polyethylene oxide terephthalate units, and washing agents that contain such soil release polymers. European Patent EP 241 984 relates to a polyester that, in addition to oxyethylene groups and terephthalic acid units, also contains substituted ethylene units as well as glycerol units. European Patent EP 241 985 discloses polyesters that, in addition to oxyethylene groups and terephthalic acid units, contain 1,2-propylene, 1,2-butylene, and/or 3-methoxy-1,2-propylene groups as well as glycerol units, and are end-capped with C1 to C4 alkyl groups. European Patent EP 253 567 relates to soil release polymers, having a molar weight from 900 to 9,000, of ethylene terephthalate and polyethylene oxide terephthalate, the polyethylene glycol units having molecular weights from 300 to 3,000 and the molar ratio of ethylene terephthalate to polyethylene oxide terephthalate being 0.6 to 0.95. European Patent Application EP 272 033 discloses polyesters, at least in part end-capped with C1-4 alkyl or acyl groups, having polypropylene terephthalate and polyoxyethylene terephthalate units. European Patent EP 274 907 describes sulfoethyl end-capped terephthalate-containing soil release polyesters. In European Patent Application EP 357 280, soil release polyesters having terephthalate, alkylene glycol, and poly-C2-4 glycol units are manufactured by sulfonation of unsaturated end groups. German Patent Application DE 26 55 551 describes the reaction of such polyesters with isocyanate-group-containing polymers, and use of the polymerizates thereby manufactured to counteract the redeposition of dirt in the context of washing synthetic fibers. German Patent DE 28 46 984 discloses washing agents that contain as a soil-release-enabling polymer, a reaction product of a polyester with a prepolymer that contains terminal isocyanate groups and is obtained from a diisocyanate and a hydrophilic nonionic macrodiol.
The majority of the polymers known from this extensive existing art have the disadvantage that they possess insufficient or no activity in the context of textiles that are not, or at least not predominantly, made of polyester. Many of today's textiles are, however, made of cotton or cotton-polyester mixed fabrics, so that a need exists for soil-release-enabling polymers that are more effective for greasy stains on such textiles.
It has now been found, surprisingly, that polymerizates obtainable from very specific monomers have a very good soil-release-enabling effect specifically on cotton-containing textiles.